Updating mongoose db with dynamic index

Question

I'm trying to update a file in my mongo document by it's index. I've managed to do it by explicitly providing the index in the query but I want the index to be variable which I can change with each request.

So I know this works:

const updateVote = await Polls.findOneAndUpdate(
        {
            "_id": ObjectId(pollId)
        },
        {
            "$inc": {
                "options.1.option.votes":1
            }
        }
        )

The 1 in options.1 is what I want to be dynamic. I tried the following but it does not work

const query = "options."+pollIndex+".option.votes"
    try{
        const updateVote = await Polls.findOneAndUpdate(
        {
            "_id": ObjectId(pollId)
        },
        {
            "$inc": {
                query:1
            }
        }
        )

The following is the full file I am trying to update

{
        "_id": "61b7342e3dcde035fcbacef9",
        "username": "johnboy",
        "title": "This is me testing the vote system",
        "description": "Hello, this is a sample description",
        "options": [
            {
                "option": {
                    "name": [
                        "sample text for option1"
                    ],
                    "votes": 25
                }
            },
            {
                "option": {
                    "name": [
                        "sample text for option2"
                    ],
                    "votes": 31
                }
            }
        ],
        "whoVoted": [
            {
                "username": "option index will go here"
            },
            {
                "username": "option index will go here"
            }
        ],
        "comments": [
            {
                "sampleUser": {
                    "comment": "sample comment",
                    "date": "Mon Dec 13 2021 22:23:18 GMT+1030 (Australian Central Daylight Time)"
                }
            }
        ],
        "createdAt": "2021-12-13T11:53:18.816Z",
        "updatedAt": "2021-12-14T00:07:49.783Z",
        "__v": 0
    }

I'm fairly new to mongo/mongoose. Any help is appreciated. thank you!